Amphotericin B, a potent antifungal agent, is a member of a class of compounds known as polyene macrolide antibiotics. These compounds are characterized by a large lactone ring which includes a chain of conjugated double bonds.
Amphotericin B, and its method of preparation from Streptomyces nodosus, is disclosed by Dutcher et al. in U.S. Pat. No. 2,908,611, issued October 13, 1959. The structure of amphotericin B is now known to be ##STR1##
The processes disclosed by Dutcher et al. for extraction and crystallization of amphotericin involve:
a. slurrying the crude amphotericin in an alcohol with an acid and thereafter neutralizing with a strong base; or
b. slurrying the crude amphotericin with dimethylformamide and treating this with an aqueous alcohol or aqueous ketone.
Michel et al. in U.S. Pat. No. 4,177,265 disclose a process for the purification of amphotericin B which utilizes a solubilizing media comprising sodium iodide or sodium thiocyanate and acetone or methanol. The use of any one of these media drastically improves the solubility of amphotericin B which otherwise has limited solubility in acetone or methanol alone.
New processes and compositions useful for the purification of amphotericin B providing a more consistent yield of highly crystalline product have been sought.